The use of macromolecules in pharmaceutical applications has received considerable attention. At times, it is desirable to couple two or more macromolecules to produce new macromolecule scaffolds with multiple activities. Existing technologies used to couple two or macromolecules, however, present numerous difficulties. For example, the alkaline conditions or high temperatures necessary to create hydrogels with high mechanical strength are cumbersome and harsh. Although the use of crosslinkers to produce macromolecular scaffolds has met with some success, the crosslinking agents are often relatively small, cytotoxic molecules, and the resulting scaffold has to be extracted or washed extensively to remove traces of unreacted reagents and byproducts (Hennink, W. E.; van Nostrum, C. F. Adv. Drug Del. Rev. 2002, 54, 13-36), thus precluding use in many medical applications. A physiologically compatible macromolecular scaffold capable of being produced in a straightforward manner is needed before they will be useful as therapeutic aids. Described herein are compounds and methods that are capable of coupling two or more molecules, such as macromolecules, under mild conditions.